Pressure-fluid-operated vise



July 28, 1959 H. T. SEALE PRESSURE-FLUID-OPERATED VISE Filed April 14. 1958 FIG. 5

, INVENTOR;

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United Staes "at This invention relates to pressure-fluid-operated vises. The principal object of this invention is to provide a pressure-fluid-operated vise which includes a novel fluidpower unit arranged to close the jaws in response to application of pressure, and simultaneously store fluid under pressure to open the jaws on release of the applied pressure.

A further object is to provide a fluid-power unit which does not require a spring return or applied pressure from a four-way control valve to opposite ends of the power unit in order to effect reciprocation of the plunger, but merely the application and release of fluid pressure.

With the above andother objects in view, as may appear hereinafter, reference is directed to the accompanying drawings in which:

Figure lis a side view of a vise equipped with a pressure-fluid operating unit;

Figure 2 is an enlarged transverse sectional view through 22 of Figure 1;

Figure 3 is a longitudinal sectional view through 33 of Figure 2, showing the pressure-fluid unit;

Figure 4 is a transverse sectional view through 4-4 of Fignre3;

Figure 5 isa diagrammatical view illustrating the. fluid operating .unit in conjunction with a control valve and pressure regulator whereby the force exerted by thevise may be readily adjusted.

The pressurefluid-operated vise includes a channelshaped housing and guide structure 1, closedat its underside by a baseplate 2 and arranged to receive a sliding beam 3. A screw shaft 4 extends through the sliding beam?) and cooperateswith a screw-threaded boss 5 secured to the base plate 2 so that the position of the sliding beam 3 maybe adjusted. "The extended end of the sliding-beam 3 carriesan adjustable jaw 6.

*S lidablymountedon top of the housing 1 is a clampingjaw 7 which cooperates with the adjustable jaw 6. The clarnping jaw 7 is providedwith a base 8. The base 8 and housing 1 may be" interconnected by dovetailed ways9. "Secured to the top of the housing 1, rearwardly of-the clamping jaw7, is afluid-power unit 10.

":The fiuid power unit 10 includes a shell 11, the underside of which may be hanged and provided with a dovetailed underside 12 which fits the ways of the housing 1. The shell 11 forms a rninorcylin der 13 anda major cylinder 14arranged in tandem. The minor cylinder is directed toward the clamping jaw 7 and is closed by an end wall 15. The major cylinder is closed by a cap lo.

Slidably mountedwithin the shell 11 is a plunger 17 which includes a stem 18, a minor piston 19 slidable in fliesrninor cylinder13, and .a major piston 29 slidable in the major cylinder 14. A bypass 21 extends through the major piston 20 and communicates with the region between the major and minor pistons 19 and 20. The end of the bypass 21 between the pistons is covered by a check-valve collar 22 formed of rubber or other elastomer.

The minor cylinder 13, end wall 15, and minor piston 19 define a minor chamber 23. The minor piston 19 2,896,487 Patented July 28, 1.959

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2 and major piston 20 define with the portion of the shell 11 therebetween an intermediate chamber 24. The major cylinder 14, major piston 20, and cap 16 define' 'amajor chamber 25. v

The cap 16 is provided with an inletport 26 communicating with the major chamber 25. The side wall bf the shell 11 is provided with a bleed port 27 normally closed by a screw-threaded plug 28 v The end wall 15 is providedwith a ventport 29 which remains open so that the mino'r chamber- 2 3 is at all times exposed to atmospheric pressure. The plunger 17 extends through the end Wall .15 and may be surrounded by a wiping gland 30. i A i Formed on the stem .18 isa shoulder fiange31 which is adapted to bear against ashoulder formed on the rearward portion of'the clamping jaw 7. This portion of the clamping jaw rnaybe provided with. a slot 32, and the stem 18 may b'eprovidedwith a tongue .33 extending into the slot and joined to the clamping jaw 7 by across pin 34. t i i The inlet port 26 is connected to .a source of pressure fluid through a valve 35 which may be .a simple threeway valve arranged to adrnit pressure fluid to the major chamber or to exhaust the pressure fluidtherefrorn.

Operation of the pressure-iiuid-operated vise .is as follows:

The adjustable jaw 6 is employed to set the spacing between the jaws to approximately the distance required to hold a workpieee so as to (minimize the requiredlen'gth oftravel of the clampingjaw 7. Upon application' of pressure fluid tothe major chambe1 25, pressure fluid is alsoapplied to the intermediatecharnber 24; as a consequence, the effective unbalanced pressure area corresponds to the area of them linor chamber 23. .The force of the pressure fl uid corresponding' to this areaistherefore applied to the clamping jaw 7.

When the pressure fluid! released from the major chambenZS, the check valve collar 22 functions to retain the pressure fluid withinthe intermediatelcharnber 24. so that an unbalancedpressure area equal to the difference in diameters of the major and minor chambers .25and 23 is effective tdre tract the pliinger 17 and clamping jaw 7. Should'jleakageoccnr in the intermediate chamber 24, itis again pressurized upon pressnrizing of the major ch mber 25'. If it is" desired to relievethe pressure in'the intermediate cham er; theplug 2 8'rnay be unscrewed. Inasmuch as the thr ce: requiredtofretractthe clamping jaw 7' needonly beenough to overcome friction, it may be quitesmjallfa's compared to the force employed in the clamping movement ofthejaw; consequently, the dilference in diameters of themajor. and minor chambers 25 and23 need notbe great. I i

Reference is directedto Figure 5. In the arrangement here illustrated a pressure regulator 36 capable of manual adjustment is connected by an external bypassline'i 37 to the intermediate chamber port 27. In this arrange ment the bypass 21 and check valve collar 22 are omitted. By adjusting the pressureof "the fluid supplied tothe intermediate chamber, the effective force exerted on. the plunger- .17 to close thevisemay be altered; that is, as the pressure in the intermediatechamber is reduced, the effective force is increased. Inasmuch as the maximum pressure in :the intermediate chamber will not exceed the pressure in themajor chamber (unless a secondj sure regulator 1 is provided, in" the control-valve line I difierence in diameters between the minor" and major chambers may be increased to give a wvider range of adjustment.

The arrangement shown in Figure 5 is particularly desirable where the force exerted by the vise must be held within close limits to prevent damage to fragile workpieces.

While particular'embodiments of this invention have been shown and described, it is not intended to limit the same to the exact details of the constructions set forth, and it embraces such changes, modifications, and equivalents of the parts and their formation and arrangement as come within the purview of the appended claims.

What is claimed is:

l. A pressure-fluid-operated vise, comprising: a vise structure including a pair of jaws, and means for slidably mounting at least one of the jaws; a shell forming a minor cylinder and a major cylinder and secured to said vise structure; a plunger having a minor piston, a major piston, and a stem extending from the minor piston and connected to said slidably mounted jaw; said shell and plunger defining a minor chamber open to atmospheric pressure, an intermediate chamber between said pistons, and a major chamber; a check-valve-controlled bypass from said major chamber to said intermediate chamber to admit pressure fluid to said intermediate chamber but prevent backflow therefrom; means for applying pressure fluid to said major chamber to move said plunger in one direction and to release pressure fluid therefrom, whereby pressure fluid in said intermediate chamber causes return movement of said plunger.

2. A pressure-fluid-operated vise, comprising: a vise structure including a pair of jaws, and means for slidably mounting at least one of the jaws; a plunger and shell means defining a vented minor chamber having a minor movable wall, a major chamber having a major movable wall, and an intermediate chamber between said movable walls; said plunger including a stem extending through said minor chamber and attached to said slidably mounted jaw; means for simultaneously applying pressure fluid at substantially equal pressure to said major and intermediate chambers whereby a pressure area corresponding to the area of said minor chamber is effective to extend said stem and said vise jaw; means for entrapping the pressure fluid in said intermediate chamber whereby on release of the pressure fluid in said major chamber a pressure area corresponding to the difference in areas of said movable walls is efiective to retract said stern and said vise jaw.

3. A pressure-fluid-power unit, comprising: a shell forming a minor cylinder and a major cylinder and secured to said vise structure; a plunger having a minor piston, a major piston, and a stem protruding axially from said shell; said shell and plunger defining a minor chamber open to atmospheric pressure, an intermediate chamber between said pistons, and a major chamber; a check-valve-controlled bypass from said major chamber to said intermediate chamber to admit pressure fluid to said intermediate chamber but prevent backflow therefrom; means for applying pressure fluid to said major chamber to move said plunger in one direction and to release pressure fluid therefrom, whereby pressure fluid in said intermediate chamber causes return movement of said plunger.

4. A pressure-fluid-power unit, comprising: a plunger and shell means defining a vented minor chamber having a minor movable wall, a major chamber having a major movable wall, and an intermediate chamber between said movable walls; said plunger including a stem protruding axially from said shell; means for simultaneously applying pressure fluid at substantially equal pressure to said major and intermediate chambers whereby a pressure area corresponding to the area of said minor chamber is effective to extend said stern; means for entrapping the pressure fluid in said intermediate chamber whereby on release of the pressure fluid in said major chamber a 4 pressure area corresponding to the difference in areas of said movable walls is effective to retract said stem.

5. A pressure-fluid-operated vise, comprising: a vise structure including a pair of jaws, and means for slidably mounting at least one of the jaws; a plunger and shell means defining a vented minor chamber having a minor movable wall, a major chamber having a major movable wall, and an intermediate chamber between said movable walls; said plunger including a stem extending through said minor chamber and attached to said slidably mounted jaw; means for applying a pressure fluid to said major chamber to drive said stem in a direction to close said vise; and means for maintaining a back pressure in said intermediate chamber tending to reduce the eflective drive on said stem and vise jaw, and operable on release of pressure in said major chamber to cause return movement of said stem to open said vise.

6. A pressure-fluid-operated vise, comprising: a vise structure including a pair of jaws, and means for slidably mounting at least one of the jaws; a plunger and shell means defining a vented minor chamber having a minor movable wall, a major chamber having a major movablewall, and an intermediate chamber between said movable walls; said plunger including a stem extending through said minor chamber and attached to said slidably mount ed jaw; means for applying a pressure fluid to said major" chamber to drive said stem in a direction to close said vise; means for maintaining a back pressure in said intermediate chamber tending to reduce the eflective drive on said stern and vise jaw, and operable on release of pressure in said major chamber to cause return movement of said stem to open said vise; and means for regulating the back pressure in said intermediate chamber thereby to control the effective drive force on said stem and clamping force exerted by said vise jaw.

7. A pressure-fluid-power unit, comprising: a plunger and shell means defining a vented minor chamber having a minor movable wall, a major chamber having a major movable wall, and an intermediate chamber between said movable walls; said plunger including a stem protruding axially from said shell; means for applying pressure fluid to said major chamber to exert a drive force in a direction to extend said stem; and means for maintaining a back pressure in said intermediate chamber tending to reduce the effective drive force on said stem, and operable on release of pressure in said major chamber to cause return movement of said stem.

8. A pessure-fluid-power unit, comprising: a plunger and shell means defining a vented minor chamber having a minor movable wall, a major chamber having a major movable wall, and an intermediate chamber between said movable walls; said plunger including a stern protruding axially from said shell; means for applying pressure fluid to said major chamber to exert a drive force in a direction to extend said stem; means for maintaining a back pressure in said intermediate chamber tending to reduce the effective drive force on said stem, and operable on release of pressure in said major chamber to cause re turn movement of said stem; and means for regulating the back pressure in said intermediate chamber thereby to control the eflective drive force on said stem. 

